Background

Cycloplegia means the paralysis of the eye’s ciliary muscle, thus the patient cannot accommodate. The power of altering the lens curvature, so that it can focus on objects which are nearby, is prevented once the ciliary muscle of the eye is paralyzed. The problems that result are similar to those caused by presbyopia, in which the lens is not flexible enough to focus on close objects. Mydriasis and pupil dilation, along with cycloplegia, commonly occur with the topical application of muscarinic receptor blockers, eg., atropine and cyclopentolate. Ocular examination and the testing of a refractive error are typical uses for alkaloids of belladonna. 

Epidemiology

The condition of cycloplegia paralyzes the ciliary muscle of the eye, thus disabling accommodation. It can result from pharmacological side effects, trauma, and underlying medical conditions, and can also be temporary or permanent. This is a very common childhood condition affecting males and females in equal proportions. The risk factors present include pre-existing conditions, regional variation, socioeconomic status, and use of medication. Questions of safety and efficacy of cycloplegic drugs in pediatric ophthalmic practice, together with the visions of effects and accommodation, dominate current clinical practice and research. If the cycloplegia is a sign of more serious medication condition, the emphasis must be on treating the cause and using the drugs safely. 

Anatomy

Pathophysiology

Cycloplegia can be defined as the paralysis of the ciliary muscle, which is responsible for eye accommodation or focusing on near objects. In addition to this, there are several reasons behind this condition including parasympathetic innervation, drugs causing cycloplegia and general mechanisms of accommodation. Examples of anticholinergics include atropine, scopolamine and tropicamide that all decrease accommodation by blocking the action of acetylcholine on ocular muscarinic receptors.

Other neurological causes are neurogenic cycloplegia, ocular neuropathy, inflammation, and trauma. The primary symptom of cycloplegia is decreased clear vision for near work due to failure to accommodate or inability to focus on close objects. Mydriasis or enlarged pupils is often seen simultaneously with it, due to the same medications or diseases affecting the parasympathetic nervous system. 

Recovery and treatment of cycloplegia are essential since drug-induced cycloplegia is generally reversible and resolves once the medication’s effects have faded. The treatment involves the pharmacological drugs to reverse the condition of cycloplegia as well as the supportive treatment directed towards treating any predisposing condition. Cycloplegia is, thus, a disorder that impairs the normal functioning of the ciliary muscle. This is usually caused by an injury to the muscle and its innervation or due to the blockage of parasympathetic nerve impulses. 

Etiology

The condition is an iatrogenic paralysis disorder of the ciliary muscle, caused by many factors. The commonest cause is drug-induced through the action of the drugs such as tropicamide, scopolamine and atropine which are cycloplegic drugs. These drugs avoid the entrance of acetylcholine into muscarinic receptors, avoiding parasympathetic activation of this ciliary muscle, hence muscular paralysis.

Other neurological causes include oculomotor nerve damage, stroke, tumors, and some neurological conditions such as Horner’s syndrome. Trauma, including physical traumas, to the ciliary muscle or the nerve supply that supplies the muscle can cause cyclotheplegia. Viral and inflammatory diseases, for example, uveitis and iritis, may affect the ciliary body, leading to inflammation or scarring that then leads to an overall cycloplegia. Even infections like herpes simplex keratitis can also affect the ciliary muscle or its innervation. Systemic diseases which involve the eyes and can cause cycloplegia either by inflammation or autoimmune injury are autoimmune diseases and endocrine disorders. Severe metabolic deregulation or endocrine abnormalities that influence neuronal activity can lead to cyclothenia.  

Other causes of cycloplegia include congenital disorders, genetic, and developmental causes. In some cases, cycloplegia can be immediate or long-term complication of some ophthalmological procedures, especially those conditions that damage the ciliary body or the lens. In other cases, idiopathic cases may exist, where the cause is unknown. 

Genetics

Prognostic Factors

The prognosis of cycloplegia varies over very wide ranges, depending on the underlying etiology. In general, neurological, traumatic, inflammatory, and systemic causes may need more complex therapy, and the results of such causes vary greatly according to the underlying ailment and the efficiency of treatment. However, drug-induced cycloplegia often has a fair prognosis with transient effects. 

Clinical History

Patient history: The other symptoms are sensitivity to light, difficulty with  close work such as reading due to poor vision, and difficulty to focus on objects that are close. 

Ocular examination: it involves the assessment of visual acuity, size of the pupils, reactivity, and signs of dilation in the pupils, together with anterior segment examination of the eye for inflammation or damage. 

Physical Examination

• Visual acuity testing: Measure visual acuity for distance and near vision, as most cycloplegia includes an effect on near vision. Conduct a cycloplegic refraction to establish refractive error and confirm loss of accommodation by using the cycloplegic agent.  
• Pupil examination: Assess pupil size, shape and reaction to light in cycloplegia. Mydriasis usually occurs due to muscle paralysis. Check for absence of accommodation reflex that is normally contracted by ciliary muscles to focus on near objects. 
• Slit-lamp examination: The anterior eye segment, like the cornea, lens and iris, may show some abnormalities in relation to cycloplegia, and inflammation or trauma could be observed in the ciliary body and its surrounding structures. 
• Fundoscopic examination: Fundoscopy should be performed to examine the retina and optic nerve. There should be no evidence of retinal pathology that might be secondary to the underlying conditions causing the cycloplegia. 
• Extraocular movements: Therefore, examination for extraocular movements should be conducted to rule out the possibility of all cranial nerve except for the 3rd cranial nerve, which would suggest additional neurological findings. 
• Intraocular pressure: IOP should be measured to rule out conditions such as glaucoma that might complicate the presentation of cycloplegia. 

Age group

Associated comorbidity

1. Stroke 
2. Diabetic neuropathy 
3. Multiple sclerosis 
4. Glaucoma 
5. Trauma 
6. Uveitis 
7. Iritis 
8. Endocrine disorders 
9. SLE 

Associated activity

Acuity of presentation

Differential Diagnoses

1. Oculomotor nerve palsy 
2. Multiple sclerosis 
3. Diabetic neuropathy 
4. Eye trauma 
5. Head trauma 
6. Uveitis 
7. Iritis 
8. Herpes simplex keratitis 
9. Syphilis 
10. Congenital anomalies 
11. Ophthalmic surgery 
12. Pseudocycloplegia 

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

Identify and treat the underlying cause. Cycloplegia occurs from a varied range of causes, including drug-induced cycloplegia, neurological disorders, trauma, inflammatory conditions, infectious conditions, systemic diseases, congenital and developmental disorders, and post-surgical complications. The management of the condition may include mere withdrawal of cycloplegic agents with supportive care. Treatment of the underlying neurological disorder, as in diabetes or stroke, also includes neuroprotective and rehabilitative treatment. Ophthalmic institute care is initiated in cases pf trauma to the eye or head, surgical repair or reconstruction is entertained if there is significant damage. Administer anti-inflammatory drugs, antibiotics/ antivirals, local treatments to reduce inflammation and aid in recovery. Systemic disorders are to be managed in a multidisciplinary approach with the help of other specialties working in the relevant fields. 

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Use of muscarinic receptor antagonists

Atropine: This is known to provide complete cycloplegia. This is established as the gold standard agent for cycloplegia.  

Cyclopentolate: This drug is known to block the action of acetylcholine which causes relaxation of the iris sphincter muscle. 

Tropicamide: It blocks acetylcholine which results in the relaxation of iris sphincter muscle. 

use-of-phases-of-management-in-treating-cycloplegia

This condition can be caused by various factors, including cycloplegic drugs, neurological conditions, trauma, inflammatory and infectious conditions. To manage these conditions, it is important to discontinue cycloplegic agents, provide supportive care, specialized interventions. 

Medication

Future Trends

Media Gallary

References

Cycloplegic and Noncycloplegic Refraction – StatPearls – NCBI Bookshelf (nih.gov)